低温等离子体对甘蔗汁杀菌效果及品质的影响

Effects of Cold Plasma on Microbial Decontamination and Quality of Sugarcane Juice

摘要:

为探明低温等离子体灭菌工艺对甘蔗汁杀菌效果和品质的影响，以甘蔗汁杀菌率、多酚氧化酶酶活（PPO）、糖组分、总酚、游离氨基酸、颜色和pH为评价指标，研究其在不同电压和时间下的变化规律。结果表明，70 kV处理4 min杀菌效果最佳，样品细菌杀菌率为1.31 lg（N₀/N），霉菌杀菌率为2.34 lg（N₀/N）。处理1 min即可使PPO活性显著降低（P<0.05）。当电压升高到50 kV以上，蔗糖质量浓度在1 min内迅速降低，葡萄糖和果糖质量浓度则迅速升高。甘蔗汁总酚和游离氨基酸质量浓度均随处理时间的延长呈先下降后上升的变化趋势，但电压越高，处理后甘蔗汁的总酚质量浓度越高，游离氨基酸含量越少。60、70 kV处理下甘蔗汁颜色变化比较明显（P<0.05）。pH值随处理时间的延长而显著降低（P<0.05），且电压越高下降速度越快。综合各项指标，40 kV处理4 min的甘蔗汁品质较好，但灭菌效果较差，进一步延长处理时间可以获得更加安全、品质更高的甘蔗汁产品。

Abstract:

To investigate the influence of cold plasma technology on microbial decontamination and quality of sugarcane juice, the sterilizing rate, polyphenol oxidase (PPO), sugar composition, total phenolic content, free amino acid content, color and pH were selected as the evaluation indicators and the changes of these indicators at different electronic voltage and handling time were analyzed. The results showed that the highest bacteria sterilizing rate, 1.31 lg(N₀/N), and the mold sterilizing rate, 2.34 lg(N₀/N), were obtained in the juice treated at 70 kV, 4 min. The activity of PPO could be inhibited significantly after treated for 1 min (P<0.05). When the voltage was higher than 50 kV, the content of sucrose decreased rapidly in 1 min，while the content of glucose and fructose were increased. The variation trends of total phenolic and free amino acid content decreased first and then increased along with the handling time. While the total phenolic content increased with the increase of electronic voltage, the free amino acid content decreased. The changes of color were significant when the electronic voltage was set at 60 kV and 70 kV(P<0.05). The pH decreased significantly during the cold plasma treatment(P<0.05), and the decrease speed under high voltage was greater than that under low voltage. Comprehensively, the juice treated under 40 kV, 4 min had the best quality, but the sterilizing efficiency was lower than that of the other treatments. In conclusion, prolong the handling time can obtain safer sugarcane juice with higher quality.